The function of the heart may be seriously impaired if any of the heart valves is not functioning properly. The heart valves may lose their ability to close properly due to disease or defects, such as (for example) by a mitral or tricuspid valve leaflet becoming partially or completely detached from a papillary muscle (e.g., by ruptured chordae tendinae) thereby resulting in prolapsing of the leaflet. The inability of the heart valve to close will cause a leak backwards, commonly referred to as regurgitation, through the valve. On the left side of the heart, regurgitation through the mitral valve may seriously impair the function of the heart 1 since a portion of the heart stroke volume of blood will return from the left ventricle to the left atrium instead of passing through the aortic valve to the organs of the body. Accordingly, the damaged heart is required to work much harder to maintain adequate circulation, a condition that inevitably ends in heart enlargement and/or heart failure.
Repairing heart structures by means of surgery often involves the use of needle and thread for attaching tissue portions together or for attaching a prosthetic implant to tissue. A traditional surgical suture typically has a needle attached to one or both ends of a thread. In a common method for attaching a suture directly to tissue (i.e., when not directly attaching tissue to tissue or tissue to implants), one needle is passed through the tissue one or several times and advanced to about the middle of the thread. The thread may or may not be knotted at this point to prevent the thread from moving slidingly through the tissue. Whether knotted or not, the end result is that the thread is attached to the tissue.
While performing heart surgery, the above technique is often used in chordae tendinae replacement. A first end of a suture thread is attached to a papillary muscle inside the left ventricle of a heart. The appropriate length of the thread is determined, and the other end of the suture thread is stitched through one or more of the leaflets of the mitral valve for creating artificial chordae tendinae. This procedure can be performed for treating a regurgitant mitral valve when the reason for the regurgitation (i.e., leak) is prolapse of a mitral valve leaflet into the left atrium. However, attaching a thread (i.e., suture) to the papillary muscle can be cumbersome due to difficulties in accessing the surgical site, including limitations in physical and visual access. The limited visual access results from the relatively narrow space between the leaflets of a mitral valve. Furthermore, access to the desired portion of the heart can be difficult while performing conventional open-heart surgery (i.e., with a sternal split). Further difficulties can arise as a result of the difficult angles at which the instruments are held.
Due to the shortcomings associated with existing medical procedures, the attachment of artificial chordae can be time consuming and may often be inaccurate. Accordingly, a need exists for improved devices and methods for creating artificial chordae. To reduce the trauma to the patient, it is desirable that the devices and methods be adapted for use in a percutaneous or minimally-invasive procedure. The present invention addresses this need.